1. Field of the Invention
Embodiments of the present invention relate to an image forming device and a starting method of the image forming device. Specifically, the embodiments relate to an image forming device and a starting method of the image forming device that can reduce start-up time.
2. Description of the Related Art
An image forming device having multiple functions, which is called a multi functional peripheral (MFP), has been known. In the image forming device, functions of devices, such as a printer, a copier, a facsimile machine, and a scanner, are integrated.
For such an image forming device, the reduction of the power consumption during a waiting state is highly desired, in addition to the reduction of the power consumption during an image forming operation. The reduction of the power consumption is achieved by providing an energy-saving mode. During the energy-saving mode, the power supply is stopped for functional blocks other than the minimum required functional blocks.
Further, it is highly desired to reduce waiting time of an operator by reducing the processing time for returning from the energy saving mode to a normal operation mode and for activating the normal operation mode when a main power supply is turned on.
An image forming device, such as an MFP, includes an engine unit, an engine control unit, and a controller. Here, the engine unit performs mechanical operations related to formation of an image, such as reading an original image or forming an image on a recording paper. The engine control unit controls operations performed by the engine unit. The controller integrally controls the whole image forming device.
The controller generates various types of control signals and transmits the control signals to the engine unit by using a communication unit, which utilizes a universal bus or the like that may require establishing a communication connection. Further, the controller transmits information which may be necessary for a starting process of the engine unit (hereinafter, referred to as starting information) to the engine control unit through the communication unit, when the main power supply is turned on, or when the operation mode of the image forming device is returning from the energy saving mode to the normal operation mode. After receiving the starting information, the engine control unit starts the engine unit.
Operations of the controller and the engine control unit at the time in which the main power supply is turned on differ from that of the controller and the engine control unit when the operation mode of the image forming device returns from the energy saving mode to the normal operation mode, depending on whether there are starting operations for the controller and the engine control unit themselves.
Namely, since the controller is not started at the time in which the main power supply is turned on, first the controller starts a starting process of the controller itself. The stating process of the controller itself includes, for example, an initializing process of a CPU. After completing the starting process of the controller itself, the controller establishes a communication connection of the communication unit between the controller and the engine control unit. After the communication connection is established, the engine control unit obtains the starting information from the controller through the communication unit, and performs the starting process. Namely, the engine control unit starts performing the starting process, after the controller is started and the communication connection between the controller and the engine control unit is established.
On the other hand, when the operation mode of the image forming device is returned from the energy saving mode to the normal mode, the controller has already been started. Thus the communication connection of the communication unit between the controller and the engine control unit is immediately established, and the engine control unit obtains the starting information from the controller and starts performing the starting process.
Therefore, there is a problem that the time to wait for the starting process of the engine unit to be completed becomes longer when the main power supply is turned on, compared to a case in which the operation mode of the image forming device returns from the energy saving mode to the normal operation mode.
Patent Document 1 (Japanese Published Unexamined Application No. 2007-301765) discloses an image forming device that addresses this problem. The image forming device includes an information transmission unit, such as a DC level transmitting unit, besides the communication unit between the controller and the engine control unit. The information transmission unit is dedicated for transmitting the starting information and does not require establishing a communication connection. The controller transmits the starting information to the engine control unit through the information transmission unit. Here, the starting information includes information indicating a cause of starting (the main power supply is turned on or the operation mode of the image forming device returns from the energy saving mode to a normal operation mode); information indicating whether an image forming unit in the engine unit is to be started; and information indicating whether an adjustment of the image forming unit is required (here, the information indicating whether elapsed time since the last image formation operation and the last image adjustment operation of the engine unit exceeds a threshold value). When the main power supply is turned on, the engine control unit starts executing a warming control for a fixing device, without waiting for establishing the communication connection of the communication unit between the controller and engine control unit, based on the starting information received through the dedicated information transmission unit. Here, the warming control for the fixing device is a part of the starting process. Similarly, when the operation mode of the image forming unit returns from the energy saving mode to the normal operation mode, based on the starting information received through the dedicated information transmission unit, the engine control unit starts executing a starting process for the image forming unit, depending on the information indicating whether the image forming unit in the engine unit is to be started; and starts executing an adjustment process for the image forming unit, depending on the information indicating whether an adjustment of the image forming unit is required.
Namely, the image forming device reduces the start-up time for the case in which the main power supply is turned on; and reduces the star-up time for the case in which the operation mode of the image forming device is returning from the energy saving mode to the normal operation mode, by performing a part of the starting process of the engine control unit in parallel with the process for establishing the communication connection of the communication unit between the controller and the engine control unit.
The image forming unit disclosed in Patent Document 1 can effectively reduce the time spent from turning on the main power supply to completing the starting process of the engine control unit, provided that the image forming device utilizes a fixing method that requires more time to warm the fixing device, such as a fixing method in which a halogen lamp is utilized for warming the fixing device.
However, for an image forming device which utilizes a fixing method in which the fixing device may be warmed within a short time period, such as a fixing method that utilizes induction heating (IH), the time spent for warming the fixing device is much less than the time spent for adjusting the image forming unit including, for example, an optical system for writing an electrostatic latent image on a photosensitive drum.
The information indicating whether an adjustment of the image forming unit is required is generated by the controller. Thus the time spent for determining the content of the information is longer for the case in which the main power supply is turned on, namely for the case in which the controller is to be started, than that of the case in which the operation mode of the image forming device is returning from the energy saving mode to the normal operation mode, namely, for the case in which the controller has already been started.
Therefore, in the image forming device disclosed in Patent Document 1, the engine control unit obtains the information indicating whether an adjustment of the image forming unit is required through the dedicated information transmission unit, only when the operation mode of the image forming device returns from the energy saving mode to the normal operation mode. On the other hand, when the main power supply is turned on, namely, when the controller is to be turned on, the engine control unit obtains the information indicating whether an adjustment of the image forming unit is required through the communication unit after the communication connection of the communication unit is established. Therefore, in the image forming unit in which the time spent for adjusting the image forming unit is much greater than the starting time of the whole image forming device, the starting time for the case in which the main power supply is turned on may not be effectively reduced.
It is desired to reduce the starting time of the whole image forming device by obtaining, as soon as possible, the information about a particular start-up process that is much greater than the time spent for the starting process of the whole image forming device. However, for some starting information such that the time spent for determining the content of the starting information depends on a cause of the starting, the information about the particular start-up process that is much greater than the time spent for the starting process of the whole image forming device is not always obtained as soon as possible.